window centering

mjolnir.lua

local window = require "mjolnir.window"
local hotkey = require "mjolnir.hotkey"

local desiredWidth = 1024
local desiredHeight = 768

hotkey.bind({"cmd", "shift"}, "m", function()
  local win = window.focusedwindow()
  local screenBounds = win:screen():frame()
  local destX = (screenBounds.w - desiredWidth) / 2 + screenBounds.x
  local destY = (screenBounds.h - desiredHeight) / 2 + screenBounds.y
  win:setframe({ x = destX, y = destY, w = desiredWidth, h = desiredHeight })
end)